With such methods and application apparatuses known from the market, objects are provided, for example, with a paint coating.
For this purpose, the object to be coated is connected to earth potential. As an opposite pole, either a negative high-voltage potential is applied to the application device, e.g. a rotary atomiser, or an ionisation device by which paint droplets or paint particles are ionised is associated with the application device.
The paint particles thus charged are attracted by the object on account of the electrical field formed between the application device and the object, are deposited on the object and discharged in the process. However, only some of the paint emitted by the application device paints reaches the object. A partial stream of the paint, which generally contains both solids and/or binders and solvents, is not applied to the object. This partial stream is called overspray in the art.
Normally, apart from the application device, all the other components of the apparatus, such as e.g. booth walls of a painting booth, are also connected to earth potential. For this reason, all the other components of the apparatus attract paint particles, so that over time more and more overspray is deposited on these components.
Normally, attempts are made to keep the deposition of overspray on other components than the object to be coated within acceptable limits by locating components at earth potential spatially as far away from the application device and the object as possible. Alternatively, use is made of covers in the form of sheets or separating means, with which the components to be protected are coated. Overspray is also carried away from the booth and deposition on the booth walls and other components is reduced by the air management and in particular the air guidance through the booth region. However, these solutions are quite expensive.
It is an object of the invention to provide a method and an apparatus of the type mentioned at the outset, which take account of these considerations.